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 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package java.net;

import java.io.FileDescriptor;
import java.io.IOException;
import java.io.InterruptedIOException;

/**
 * Abstract datagram and multicast socket implementation base class.
 *
 * @author Pavani Diwanji
 * @since JDK1.1
 */

public abstract class DatagramSocketImpl implements SocketOptions {

  /**
   * The local port number.
   */
  protected int localPort;

  /**
   * The file descriptor object.
   */
  protected FileDescriptor fd;

  int dataAvailable() {
    // default impl returns zero, which disables the calling
    // functionality
    return 0;
  }

  /**
   * The DatagramSocket or MulticastSocket
   * that owns this impl
   */
  DatagramSocket socket;

  void setDatagramSocket(DatagramSocket socket) {
    this.socket = socket;
  }

  DatagramSocket getDatagramSocket() {
    return socket;
  }

  /**
   * Creates a datagram socket.
   *
   * @throws SocketException if there is an error in the underlying protocol, such as a TCP error.
   */
  protected abstract void create() throws SocketException;

  /**
   * Binds a datagram socket to a local port and address.
   *
   * @param lport the local port
   * @param laddr the local address
   * @throws SocketException if there is an error in the underlying protocol, such as a TCP error.
   */
  protected abstract void bind(int lport, InetAddress laddr) throws SocketException;

  /**
   * Sends a datagram packet. The packet contains the data and the
   * destination address to send the packet to.
   *
   * @param p the packet to be sent.
   * @throws IOException if an I/O exception occurs while sending the datagram packet.
   * @throws PortUnreachableException may be thrown if the socket is connected to a currently
   * unreachable destination. Note, there is no guarantee that the exception will be thrown.
   */
  protected abstract void send(DatagramPacket p) throws IOException;

  /**
   * Connects a datagram socket to a remote destination. This associates the remote
   * address with the local socket so that datagrams may only be sent to this destination
   * and received from this destination. This may be overridden to call a native
   * system connect.
   *
   * <p>If the remote destination to which the socket is connected does not
   * exist, or is otherwise unreachable, and if an ICMP destination unreachable
   * packet has been received for that address, then a subsequent call to
   * send or receive may throw a PortUnreachableException.
   * Note, there is no guarantee that the exception will be thrown.
   *
   * @param address the remote InetAddress to connect to
   * @param port the remote port number
   * @throws SocketException may be thrown if the socket cannot be connected to the remote
   * destination
   * @since 1.4
   */
  protected void connect(InetAddress address, int port) throws SocketException {
  }

  /**
   * Disconnects a datagram socket from its remote destination.
   *
   * @since 1.4
   */
  protected void disconnect() {
  }

  /**
   * Peek at the packet to see who it is from. Updates the specified {@code InetAddress}
   * to the address which the packet came from.
   *
   * @param i an InetAddress object
   * @return the port number which the packet came from.
   * @throws IOException if an I/O exception occurs
   * @throws PortUnreachableException may be thrown if the socket is connected to a currently
   * unreachable destination. Note, there is no guarantee that the exception will be thrown.
   */
  protected abstract int peek(InetAddress i) throws IOException;

  /**
   * Peek at the packet to see who it is from. The data is copied into the specified
   * {@code DatagramPacket}. The data is returned,
   * but not consumed, so that a subsequent peekData/receive operation
   * will see the same data.
   *
   * @param p the Packet Received.
   * @return the port number which the packet came from.
   * @throws IOException if an I/O exception occurs
   * @throws PortUnreachableException may be thrown if the socket is connected to a currently
   * unreachable destination. Note, there is no guarantee that the exception will be thrown.
   * @since 1.4
   */
  protected abstract int peekData(DatagramPacket p) throws IOException;

  /**
   * Receive the datagram packet.
   *
   * @param p the Packet Received.
   * @throws IOException if an I/O exception occurs while receiving the datagram packet.
   * @throws PortUnreachableException may be thrown if the socket is connected to a currently
   * unreachable destination. Note, there is no guarantee that the exception will be thrown.
   */
  protected abstract void receive(DatagramPacket p) throws IOException;

  /**
   * Set the TTL (time-to-live) option.
   *
   * @param ttl a byte specifying the TTL value
   * @throws IOException if an I/O exception occurs while setting the time-to-live option.
   * @see #getTTL()
   * @deprecated use setTimeToLive instead.
   */
  @Deprecated
  protected abstract void setTTL(byte ttl) throws IOException;

  /**
   * Retrieve the TTL (time-to-live) option.
   *
   * @return a byte representing the TTL value
   * @throws IOException if an I/O exception occurs while retrieving the time-to-live option
   * @see #setTTL(byte)
   * @deprecated use getTimeToLive instead.
   */
  @Deprecated
  protected abstract byte getTTL() throws IOException;

  /**
   * Set the TTL (time-to-live) option.
   *
   * @param ttl an {@code int} specifying the time-to-live value
   * @throws IOException if an I/O exception occurs while setting the time-to-live option.
   * @see #getTimeToLive()
   */
  protected abstract void setTimeToLive(int ttl) throws IOException;

  /**
   * Retrieve the TTL (time-to-live) option.
   *
   * @return an {@code int} representing the time-to-live value
   * @throws IOException if an I/O exception occurs while retrieving the time-to-live option
   * @see #setTimeToLive(int)
   */
  protected abstract int getTimeToLive() throws IOException;

  /**
   * Join the multicast group.
   *
   * @param inetaddr multicast address to join.
   * @throws IOException if an I/O exception occurs while joining the multicast group.
   */
  protected abstract void join(InetAddress inetaddr) throws IOException;

  /**
   * Leave the multicast group.
   *
   * @param inetaddr multicast address to leave.
   * @throws IOException if an I/O exception occurs while leaving the multicast group.
   */
  protected abstract void leave(InetAddress inetaddr) throws IOException;

  /**
   * Join the multicast group.
   *
   * @param mcastaddr address to join.
   * @param netIf specifies the local interface to receive multicast datagram packets
   * @throws IOException if an I/O exception occurs while joining the multicast group
   * @since 1.4
   */
  protected abstract void joinGroup(SocketAddress mcastaddr,
      NetworkInterface netIf)
      throws IOException;

  /**
   * Leave the multicast group.
   *
   * @param mcastaddr address to leave.
   * @param netIf specified the local interface to leave the group at
   * @throws IOException if an I/O exception occurs while leaving the multicast group
   * @since 1.4
   */
  protected abstract void leaveGroup(SocketAddress mcastaddr,
      NetworkInterface netIf)
      throws IOException;

  /**
   * Close the socket.
   */
  protected abstract void close();

  /**
   * Gets the local port.
   *
   * @return an {@code int} representing the local port value
   */
  protected int getLocalPort() {
    return localPort;
  }

  <T> void setOption(SocketOption<T> name, T value) throws IOException {
    if (name == StandardSocketOptions.SO_SNDBUF) {
      setOption(SocketOptions.SO_SNDBUF, value);
    } else if (name == StandardSocketOptions.SO_RCVBUF) {
      setOption(SocketOptions.SO_RCVBUF, value);
    } else if (name == StandardSocketOptions.SO_REUSEADDR) {
      setOption(SocketOptions.SO_REUSEADDR, value);
    } else if (name == StandardSocketOptions.IP_TOS) {
      setOption(SocketOptions.IP_TOS, value);
    } else if (name == StandardSocketOptions.IP_MULTICAST_IF &&
        (getDatagramSocket() instanceof MulticastSocket)) {
      setOption(SocketOptions.IP_MULTICAST_IF2, value);
    } else if (name == StandardSocketOptions.IP_MULTICAST_TTL &&
        (getDatagramSocket() instanceof MulticastSocket)) {
      if (!(value instanceof Integer)) {
        throw new IllegalArgumentException("not an integer");
      }
      setTimeToLive((Integer) value);
    } else if (name == StandardSocketOptions.IP_MULTICAST_LOOP &&
        (getDatagramSocket() instanceof MulticastSocket)) {
      setOption(SocketOptions.IP_MULTICAST_LOOP, value);
    } else {
      throw new UnsupportedOperationException("unsupported option");
    }
  }

  <T> T getOption(SocketOption<T> name) throws IOException {
    if (name == StandardSocketOptions.SO_SNDBUF) {
      return (T) getOption(SocketOptions.SO_SNDBUF);
    } else if (name == StandardSocketOptions.SO_RCVBUF) {
      return (T) getOption(SocketOptions.SO_RCVBUF);
    } else if (name == StandardSocketOptions.SO_REUSEADDR) {
      return (T) getOption(SocketOptions.SO_REUSEADDR);
    } else if (name == StandardSocketOptions.IP_TOS) {
      return (T) getOption(SocketOptions.IP_TOS);
    } else if (name == StandardSocketOptions.IP_MULTICAST_IF &&
        (getDatagramSocket() instanceof MulticastSocket)) {
      return (T) getOption(SocketOptions.IP_MULTICAST_IF2);
    } else if (name == StandardSocketOptions.IP_MULTICAST_TTL &&
        (getDatagramSocket() instanceof MulticastSocket)) {
      Integer ttl = getTimeToLive();
      return (T) ttl;
    } else if (name == StandardSocketOptions.IP_MULTICAST_LOOP &&
        (getDatagramSocket() instanceof MulticastSocket)) {
      return (T) getOption(SocketOptions.IP_MULTICAST_LOOP);
    } else {
      throw new UnsupportedOperationException("unsupported option");
    }
  }

  /**
   * Gets the datagram socket file descriptor.
   *
   * @return a {@code FileDescriptor} object representing the datagram socket file descriptor
   */
  protected FileDescriptor getFileDescriptor() {
    return fd;
  }
}
